This project will create a nationally representative 1-in-100 Public Use Microdata Sample (PUMS) of the 1910 United States Population Census to be disseminated through the National Archives, the Inter-University Consortium for Political and Social Research, and via the Internet. Preparation of the 1910 PUMS involves seven steps: 1) Data entry of information on approximately 946,290 individuals from the original enumerators' manuscripts, including a flat 1-in-100 sample of 919,720 persons in the general population and a 1-in-100 oversample of 26,570 Native Americans; 2) Development of dictionaries to translate each alphabetic entry into numeric codes compatible with the existing series of microdata for other census years; 3) Evaluation of sample quality through consistency checks, random blind verification, and comparison with aggregate statistics in the published census volumes; 4) Editing, cleaning, and allocation of missing, illegible, and inconsistent data through logical rule and imputation procedures; 5) Construction of new variables on household composition, relationships within families, economic status, and ethnicity; 6) Development of documentation; and 7) Integration of the sample and documentation into the Integrated Public Use Microdata Series (IPUMS). The 1910 population census is the only early-twentieth century census to include information about remarriage, employment status, language spoken, or veteran status and the first census to include questions on mother tongue, mother's mother tongue, father's mother tongue, industry, and class of worker. Unlike the 1920 and 1930 censuses, it includes key inquiries on number of children ever born, number of children surviving, and duration of marriage. These variables shed light on the accelerating pace of immigration and industrialization, and the decline of fertility and mortality. Thus, a sample of the 1910 census will not only provide a critical link in the existing series of public use samples; it will also greatly enrich our understanding of American society in a pivotal period.